Ortho Infections Flashcards
Why is staph aureus having an increased resistance to antibiotics?
Plasmids
When do bacteria enter the body?
Altered hemostasis
In regards to blood supply, when does the risk of infection increase?
Decreased blood supply
What increases microcirculation & vasodilation?
Warming of the source of infection
How does a traumatic injury & the presence of implants increase the risk of infection?
Periosteal injury, micro/macrovascular compromise
Bacteria have affinity for exposed sites
Form glycocalyx capsule
Impair normal immune function & abx penetration
Factors that Decrease Local Immune Responses
Decreased blood flow
Neuropathy
Trauma
Medication
Medications that can Decrease the Local Immune Response
NSAIDs
Rheum
Steroids
Factors that Decrease the Systemic Immune Response
Renal & liver disease DM ETOH Rheum diseases Immunocompromised state Malnutrition
Diagnostic Test with Musculoskeletal Infections
H&P
Labs
Culture of fluid or tissue
Presentation of a Musculoskeletal Infection
Pain Warmth Swelling Redness Refusal to bear weight (esp. children) Fever/chills Night sweats N/V Loss of joint motion
Labs to Diagnose Musculoskeletal Infections
CBC with differential ESR CRP Blood cultures Gram stain Frozen section PCR: polymerase chain reaction
When does ESR elevate in infection?
Within 2 days of infection
When does CRP elevate, peak, and return to normal in an infection?
E: within 6 hours
P: 48 hours
Return: 1 week after appropriate treatment
What is the best indicator for diagnosis & monitoring treatment of an infection?
CRP
What diagnostic modality has shown to be helpful in peri-prosthetic infections?
IL-6
Things you can see on Plain Films for Musculoskeletal Infections
Soft tissue swelling
Loss of tissue planes
Bony changes (40+% loos to see)
Brodies Abscess
Other Radiologic Tests to Detect Musculoskeletal Infections
Bone scan: vague Indium 111 leukocyte nuclear scan Gallium citrate scan PET scan MRI
What diagnostic modality is used frequently for infection?
MRI
When do musculoskeletal infections frequently happen?
Open fractures
DM
Recent surgery
Describe Hematogenous Osteomyelitis
Osteomyelitis which was transferred by the blood
Desccribe Contiguous Focus Osteomyelitis
Infection caused by a prior infection
Classification of Musculoskeletal Infections that Describes the Anatomic Involvement
Stage 1: medullary
Stage 2: superficial
Stage 3: localized
Stage 4: diffuse
Classification of Musculoskeletal Infections that Describes the Host
Normal
Compromised
Treatment worse than disease
Most Common Sites of Hematogenous Osteomyelitis
Vertebrae***
Long bones
Pelvis
Clavicle
Vertebral Osteomyelitis
50+
May involve 2 vertebrae + disc
Most Common Bug with Hematogenous Osteomyelitis
S. aureus
Most Common Bugs in Vertebral Osteomyelitis
S. aureus
Pseudomonas (IVDU)
Presentation of Vertebral Osteomyelitis
Fever
Pain over area
Possible: meningitis, abscesses
Most Common Reasons for Contiguous-Focus Osteomyelitis without General Vascular Insufficiency
Trauma with direct contact to bone Infection from soft tissue Nosocomial infection ORIF Prosthetics Open fractures Chronic soft tissue infections
When does a continguous-focused osteomyelitis without general vascular insufficiency occur?
About 1 month after primary cause of infection
Presentation & Sequelae of Contiguous-Focus Osteomyelitis without General Vascular Insufficiency
P: pain, fever, drainage of area
S: decreased bone stability, necrosis, & soft tissue damage
Most Common Bugs with Contiguous-Focus Osteomyelitis with General Vascular Insufficiency
Staph
Strep
Enterococcus
G-bacilli
Presentation of Contiguous-Focus Osteomyelitis with General Vascular Insufficiency
Ulcers
Multiple foot problems
DM
Chronic OSteomyelitis
H/O osteomyelitis
Recurrence of pain, fever, drainage, erythema, & swelling
Nidus of infection must be removed
Prolonged can develop SCC or amyloidosis
Diagnosis of Musculoskeletal Infections in Adults
H&P
Labs
Imaging
Osteomyelitis: great mimicker
Treatment of Musculoskeletal Infections in Adults
Antibiotics: 4-6 weeks
Adequate drainage, debridement, dead space management, maintenance of blood supply/wound care
Treat systemic issues
Treatment of Musculoskeletal Infections in Adults from Last Debridement
Stage 1: medullary (4 weeks antibiotics)
Stage 2: superficial (2 weeks antibiotics)
Stage 3: localized (4-6 weeks antibiotics)
Stage 4: diffuse (4-6 weeks antibiotics)
Treatment of Musculoskeletal Infections in Adults When Surgery is not an Option
Rifampin + fluoroquinolone or Bactrim for 6 months
Possible long term suppression
Surgical Debridement of Musculoskeletal Infections
Complete when bone bleeds “paprika sign”
Dead = remove
FB = remove
Bony defects: autograft or ex. fix
Alternative Treatment of Musculoskeletal Infections in Adults
Antibiotic impregnated beads: high concentrations of antibiotics &
fills dead space
Antibiotic pumps
Can fractures heal in the setting of infection?
Yes
Stable better than unstable
Int./Ex. fixation
Types of Coverage of Soft Tissue Injuries
Wound pumps
Flaps
Skin grafts
Avoid secondary intention
Hyperbaric Oxygen Therapy for Musculoskeletal Infections in Adults
Useful for chronic osteomyelitis & soft tissue injuries
Benefits of Hyperbaric Oxygen Therapy in Musculoskeletal Infections in Adults
Promotes collagen formation & angiogenesis
Increases oxygen tension in soft tissues
Cons to Hyperbaric Oxygen Therapy in Musculoskeletal Infections in Adults
Expensive
Multiple sessions
Possible Routes of Adult Septic Osteoarthritis
Blood
Trauma
Contiguous spread
IVDU
Predisposing Factors for Adult Septic Arthritis
DM Rheum Steroid use HIV Malignancy Age
Most Common Joint Affected from Adult Septic Arthritis
Knee
Pathophysiology of Adult Septic Arthritis
Destruction of synovial cell lining
Glycosaminoglycan destruction
Increase inflammatory response
Destruction of cartilage
Most Common Organisms for Adult Septic Arthritis
N. gonorrhea S. aureus (IVDU) E. coli Pseudomonas Fungal (HIV)
Presentation of Adult Septic Arthritis
Warm, swollen, & painful joint
Infectious Blood Work for Adult Septic Arthritis
CBC
ESR
CRP
What are we looking for when we send an aspiration sample?
Cell count with differential
Crystals
Gram stain
Cultures
Treatment of Adult Septic Arthritis
Surgery
Immediate antibiotics
Arthrotomy & debridement
NSAIDs: decreases cartilage damage
Most Common Location of Musculoskeletal Infections in Pediatric Patients
High vascular areas at the metaphysical epiphyseal are
Most Common Organisms for Pediatric Musculoskeletal Infections
S. aureus Group A strep H. influenza Kingella kingae (URI presentation) Salmonella (sickle cell) Bartonella henselae (cat scratch disease) P. aeruginosa (feet)
Pathophysiology of Osteomyelitis in Neonates
Infection perforates periosteum
Spreads to surrounding tissue & joints
Pathophysiology of Osteomyelitis in Infants
More rare due to metaphyseal capillary atrophy
How is osteomyelitis spread limited in children?
Thickening of the cortex of bones
Diagnosing Musculoskeletal Infections in Pediatrics
Fever + limb pain for 3+ days needs evaluation
Presentation of Musculoskeletal Infections in Neonates
Pseudoparalysis
Pain with palpation
Swelling
Decreased appetite
Presentation of Musculoskeletal Infections in Infants, Toddlers, & Young Children
Fever of Unknown Origin Limp or non-weight bearing Swelling Warmth Erythema
Presentation of Musculoskeletal Infections in Older Children & Adolescents
Constant localized pain
Fever
Diagnosis of Pediatric Musculoskeletal Infections
Blood cultures
US: hips
MRI with gadolinium
Treatment of Pediatric Musculoskeletal Infections
Antibiotics (4-6 weeks)
Decompression & drainage of infected area
Antibiotics Need to Cover What Organisms
Staph
Group B strep
Treatment of Chronic Osteomyelitis
I&D
Antibiotics: 6-12 months
Most Common Organisms for Pediatric Septic Arthritis
S. aureus
Group B strep (neonates)
Gram negative bacilli (neonates)
Presentation of Pediatric Septic Arthritis
Fever Edema Erythema Effusion Refusal to ambulate Pseudo paralysis After 72 hours of infection
Presentation of a Pediatric Septic Hip Arthritis
Flexed
Abducted
External rotation
Severe pain with PROM & rotation
Diagnosis of a Pediatric Septic Hip Arthritis
Infectious blood work
Plain films: r/o other diagnoses
Hip aspiration (gold standard-impractical)
Hip US: sagging rope sign
Treatment of Pediatric Septic Arthritis
Antibiotics: 3+ weeks
Drainage of joint
Possible Sequelae of Pediatric Septic Arthritis
Potential growth plate disturbances
Most Common Organisms in Periprosthetic Infections
S. aureus
S. epidermadis
How to periprosthetic infections occur?
Direct contact in surgery
After surgery (draining incision)
Hematogenous inoculation
Symptoms of Periprosthetic Infections
Pain not changed by activity levels
Stiffness
Chronic drainage
Diagnosis of Periprosthetic Infections
Symptoms Infectious labs Aspiration Plain radiographs (late finding) Bone scan: "hot spot" Indium-111 nuclear scan
Short Term Periprosthetic Infections
Less than 4-6 weeks post surgery
Hematogenous spread
Long Term Periprosthetic Infections
> 4-6 weeks after surgery
No inciting event
Chronic pain
Treatment Options for Periprosthetic Infections
Antibiotics alone Single stage revision 2 stage revision Amputation Fusion
Single Stage Revision for Periprosthetic Infections
Short term infections
Surgical debridement
Antibiotics 6 weeks (2 drugs)
Single oral therapy for at least 1 year
Two Stage Revision for Periprosthetic Infections
Long term infections Surgical debridement Antibiotic cement spacer Antibiotics 6 weeks Antibiotic holiday (2 weeks) Infectious blood work "Normal" blood work- revision arthroplasty Abnormal blood work- start over with surgical debridement Year of antibiotics
Indications for Amputations in Periprosthetic Infections
Life-threatening sepsis
Multiple failed revisions
Persistent severe pian
Indications for Fusion in Periprosthetic Infections
Total knee arthroplasty High functioning patients Single joint Young patient Loss of extensor mechanism
Prevention of Periprosthetic Infections
Antibiotic prophylaxis for invasive procedures for life
Antibiotics: amoxicillin, cephalosporin, or clindamycin